After years of futile efforts, it looks as if the Montreal Symphony Orchestra may finally get the new home it’s always wanted. A plan being floated by the new Quebec government would abandon the idea of building a $280 million performance complex, and instead renovate an existing (and terribly underused) theater for the orchestra’s use. The plan is likely to succeed where others have failed partly because it is simple, but mostly because it won’t cost the province’s taxpayers a dime.